Standard Lemma guide

cytosine

noun · 2 senses · updated from the 2026-07-25 local source snapshot

Definitions and examples are grouped by meaning. Pronunciation, history, word forms, translations, descendants, synonyms, antonyms, derived terms, and related words appear whenever the source provides them.

Sound

Pronunciation

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  • /ˈsaɪtəsiːn/
  • US: Recorded audio is listed in the source snapshot.
  • UK: Recorded audio is listed in the source snapshot.

1

noun

Meaning 1

A heterocyclic base, 4-aminopyrimidin-2(1H)-one, which pairs with guanine in DNA and RNA (by means of three hydrogen bonds).

Definition source: English Wiktionary via Wiktextract

Topics: biochemistry, biology, chemistry, microbiology, natural-sciences, physical-sciences

No example sentence was provided for this meaning.

Meaning relationships

Synonyms: none provided

Antonyms: none provided

Broader terms: nucleobase, pyrimidine

2

noun

Meaning 2

a base found in DNA and RNA and derived from pyrimidine; pairs with guanine

Definition source: Princeton WordNet 3.0

No example sentence was provided for this meaning.

Meaning relationships

Synonyms: C

Antonyms: none provided

Broader terms: pyrimidine

History

Etymology

After German Cytosin, equivalent to Ancient Greek κύτος (kútos) + -ine. Cytosine was discovered and named by the German biochemists Albrecht Kossel and Albert Neumann in 1894 when it was hydrolyzed from calf thymus tissues.

Across languages

Translations

21 source translations are retained for this English entry.

  • Catalan: citosina — heterocyclic base, 4-aminopyrimidin-2(1H)-one, which pairs with guanine in DNA and RNA
  • Chinese Mandarin: 胞嘧啶 (bāomìdìng) — heterocyclic base, 4-aminopyrimidin-2(1H)-one, which pairs with guanine in DNA and RNA
  • Czech: cytosin — heterocyclic base, 4-aminopyrimidin-2(1H)-one, which pairs with guanine in DNA and RNA
  • Esperanto: citozino — heterocyclic base, 4-aminopyrimidin-2(1H)-one, which pairs with guanine in DNA and RNA
  • Finnish: sytosiini — heterocyclic base, 4-aminopyrimidin-2(1H)-one, which pairs with guanine in DNA and RNA
  • French: cytosine — heterocyclic base, 4-aminopyrimidin-2(1H)-one, which pairs with guanine in DNA and RNA
  • Galician: citosina — heterocyclic base, 4-aminopyrimidin-2(1H)-one, which pairs with guanine in DNA and RNA
  • German: Cytosin — heterocyclic base, 4-aminopyrimidin-2(1H)-one, which pairs with guanine in DNA and RNA
  • Hungarian: citozin — heterocyclic base, 4-aminopyrimidin-2(1H)-one, which pairs with guanine in DNA and RNA
  • Icelandic: sýtósín — heterocyclic base, 4-aminopyrimidin-2(1H)-one, which pairs with guanine in DNA and RNA
  • Icelandic: sýtosín — heterocyclic base, 4-aminopyrimidin-2(1H)-one, which pairs with guanine in DNA and RNA
  • Irish: cíotóisín — heterocyclic base, 4-aminopyrimidin-2(1H)-one, which pairs with guanine in DNA and RNA
  • Italian: citosina — heterocyclic base, 4-aminopyrimidin-2(1H)-one, which pairs with guanine in DNA and RNA
  • Japanese: シトシン (shitoshin) — heterocyclic base, 4-aminopyrimidin-2(1H)-one, which pairs with guanine in DNA and RNA
  • Polish: cytozyna — heterocyclic base, 4-aminopyrimidin-2(1H)-one, which pairs with guanine in DNA and RNA
  • Portuguese: citosina — heterocyclic base, 4-aminopyrimidin-2(1H)-one, which pairs with guanine in DNA and RNA
  • Russian: цитози́н (citozín) — heterocyclic base, 4-aminopyrimidin-2(1H)-one, which pairs with guanine in DNA and RNA
  • Serbo-Croatian: citòzīn — heterocyclic base, 4-aminopyrimidin-2(1H)-one, which pairs with guanine in DNA and RNA
  • Spanish: citosina — heterocyclic base, 4-aminopyrimidin-2(1H)-one, which pairs with guanine in DNA and RNA
  • Turkish: sitozin — heterocyclic base, 4-aminopyrimidin-2(1H)-one, which pairs with guanine in DNA and RNA
  • Ukrainian: цитозин (cytozyn) — heterocyclic base, 4-aminopyrimidin-2(1H)-one, which pairs with guanine in DNA and RNA